Downtown Vienna:

1. Sundial at St. Stephen’s Cathedral, Stephansplatz (map): This clock was designed by the medieval astronomer Georg von Peuerbach in 1451. It is Vienna’s oldest sundial, fixed onto the exterior south face of the Cathedral. Since the Cathedral’s facade is often covered by scaffolding as it is being cleaned, it is not always visible.How to get there: Take U-Bahn line U1 from Kaisermühlen VIC to Stephansplatz.

2. The Old University Observatory, Ignaz-Seipl-Platz (map): The headquarters of the Austrian Academy of Sciences was formerly a university building with an observatory built onto the roof. Even at that time, the location was not suitable for astronomical observations as the air quality was poor. The observatory did not have a dome construction, like we would expect nowadays, with observations made through high windows instead. The observatory has since been removed from the building.How to get there: Take the U-Bahn line U1 from Kaisermühlen VIC to Stephansplatz.

3. Elisabeth Freiin von Matt’s private observatory, Kumpfgasse 1 (map), was the location of Elisabeth Freiin von Matt’s private observatory. She carried out numerous measurements and was one of the first women to publish them. After her death, her high-quality instruments went to the Vienna University Observatory and some of them are still in their possession today.How to get there: Take the U-Bahn line U1 from Kaisermühlen VIC to Stephansplatz.

4. The Jesuit Observatory, Bäckerstraße/Postgasse (map): Although the building no longer exists, this is the site of one of the first observatories built in Vienna. The Director of the observatory, Maximilian Hell, later became Director of the Old University Observatory (above). After visiting the location, you can compare the modern-day street (Postgasse) with a painting by Bernardo Bellotto, also known as Canaletto, who painted the square with the observatory. The painting is displayed at Kunsthistorisches Museum (see below).How to get there: Take the U-Bahn line U1 from Kaisermühlen VIC to Stephansplatz, then U-Bahn line U3 in the direction heading to Stubentor.

5. Kunsthistorisches Museum Wien (History of Art Museum Vienna), Maria-Theresien-Platz (map): Among its collection, you’ll find paintings that reveal how the Old University Observatory and the Jesuit Observatory looked in their heyday. Head to the second floor and enter the permanent exhibition — Canaletto’s paintings are displayed in the first room. You can also find various artefacts on the floor below (enter “Kunstkammer Wien”), such as sundials, astrolabes, celestial globes and astronomical table clocks. Unlike the other places listed on this page, there is an entrance fee (€15.00).How to get there: Take U-Bahn line U1 from Kaisermühlen VIC to Stephansplatz, then U-Bahn line U3 to Volkstheater.

Further out:

6. Rudolf König’s observatory, Kupelwiesergasse 12, Hietzing (map): The merchant Rudolf König was a self-taught astronomer who built an observatory for his studies in 1906 at Hietzing, which was a rural location in those days. He determined the positions of 8,000 celestial objects and mapped the Moon (a lunar crater is named after him for his efforts). After his death, the telescopes were sold to an observatory in Prague and are still in use today at Štefánik’s Observatory. The dome at König’s former residence is the original structure, but it is sealed and in a poor condition. Since the house is privately owned, the observatory can only be viewed from the street.How to get there: Take the U-Bahn line U1 from Kaisermühlen VIC to Karlsplatz, then take the U4 line to Hietzing, and from there the tram 60 to Gloriettegasse. The observatory is then a 5-minute walk away. (Villa Fantastica, shown below, is only a 2-minute walk from this location.)

7. Villa Fantastica, Neue Welt Gasse 12 (map): A library full of science fiction literature! The collection is extensive and contains books in many different languages. Since it is run on a voluntary basis, it is not open every day. Open on Tuesdays and Thursdays 13:30-18:30 and on Saturdays 11:00-15:00.How to get there: Take the U-Bahn line U1 from Kaisermühlen VIC to Karlsplatz, then take the U4 line to Hietzing, and from there the tram 60 to Gloriettegasse. The library is then a 5-minute walk away. (Rudolf König’s observatory, shown above, is only a 2-minute walk from this location.)

8. Freiluftplanetarium Sterngarten (open-air planetarium star garden) in Georgenberg (map): The construction of the site started in 1997 and it is fairly unique. Standing on the platform in the centre, the columns to the east and west show sunrises and sunsets during the year, the pillar to the south has markings that shows the midday height of the Sun during the summer and winter solstices and the equinoxes. The tip of the north pillar shows Polaris. In addition, the north pillar also casts a shadow on an analemma on the ground where the current date can be read at noon.How to get there: Take the U-Bahn line U1 to Karlsplatz, then the U4 line direction to Hietzing, and from there you take a bus 56A to Valentingasse. You still have to walk 15 minutes from there to the star garden. Difficult to reach, but worth a visit! And it is close to the Planet walk (below), too.

9. Planet walkat the wall of the Lainzer Tiergarten (map): Find the Sun at the end of Wittgensteinstraße. From there, you can stroll easily to the planets Mercury, Venus, Earth and Mars (within 20 minutes), but to complete the walk to Pluto (it was established before 2006, so Pluto is included), you should set aside about 4 hours in total for the 6 kilometre journey in each direction (you have to return to where you started as there is no public transport available on the other end).How to get there: Take the U1 to Karlsplatz, then the U4 direction Hütteldorf to Hietzing. Take bus 56A from Hietzing to Wittgensteinstraße. (Or from the star garden, shown above, just walk through Maurer Wald until you hit the wall of Lainzer Tiergarten.)

10. Solar System street signs in Hütteldorf (map): On the Wolfersberg in the west of Vienna, streets are named after the Sun, Moon and the planets. There is also a Sirius road. There is no street sign for Pluto as the naming was done before the planet was discovered.How to get there: Take the U-Bahn line U1 to Karlsplatz, then the U4 line to Hütteldorf, then bus 52A to Campingplatz Wien-West 2 (3 stops).